Recommendation ITU-R P.1411-6(02/2012)

Propagation data and prediction methods

for the planning of short-range outdoor radiocommunication systems and radio

local area networks in the frequencyrange 300 MHz to 100 GHz

P SeriesRadiowave propagation

ii Rec. ITU-R P.1411-6

Foreword

The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted.

The regulatory and policy functions of the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups.

Policy on Intellectual Property Right (IPR)

ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and licensing declarations by patent holders are available from http://www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be found.

Series of ITU-R Recommendations(Also available online at http://www.itu.int/publ/R-REC/en)

Series Title

BO Satellite deliveryBR Recording for production, archival and play-out; film for televisionBS Broadcasting service (sound)BT Broadcasting service (television)F Fixed serviceM Mobile, radiodetermination, amateur and related satellite servicesP Radiowave propagationRA Radio astronomyRS Remote sensing systemsS Fixed-satellite serviceSA Space applications and meteorologySF Frequency sharing and coordination between fixed-satellite and fixed service systemsSM Spectrum managementSNG Satellite news gatheringTF Time signals and frequency standards emissionsV Vocabulary and related subjects

Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1.

Electronic PublicationGeneva, 2012

ITU 2012

All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without written permission of ITU.

Rec. ITU-R P.1411-6 1

RECOMMENDATION ITU-R P.1411-6

Propagation data and prediction methods for the planning of short-rangeoutdoor radiocommunication systems and radio local area networks

in the frequency range 300 MHz to 100 GHz(Question ITU-R 211/3)

(1999-2001-2003-2005-2007-2009-2012)

Scope

This Recommendation provides guidance on outdoor short-range propagation over the frequency range 300 MHz to 100 GHz. Information is given on path loss models for line-of-sight (LoS) and non-line-of-sight (NLoS) environments, building entry loss, multipath models for both environments of street canyon and over roof-tops, number of signal components, polarization characteristics and fading characteristics.

The ITU Radiocommunication Assembly,

considering

a) that many new short-range (operating range less than 1 km) mobile and personal communication applications are being developed;

b) that there is a high demand for radio local area networks (RLANs) and wireless local loop systems;

c) that short-range systems using very low power have many advantages for providing services in the mobile and wireless local loop environment;

d) that knowledge of the propagation characteristics and the interference arising from multiple users in the same area is critical to the efficient design of systems;

e) that there is a need both for general (i.e. site-independent) models and advice for initial system planning and interference assessment, and for deterministic (or site-specific) models for some detailed evaluations,

noting

a) that Recommendation ITU-R P.1238 provides guidance on indoor propagation over the frequency range 900 MHz to 100 GHz, and should be consulted for those situations where both indoor and outdoor conditions exist;

b) that Recommendation ITU-R P.1546 provides guidance on propagation for systems that operate over distances of 1 km and greater, and over the frequency range 30 MHz to 3 GHz,

recommends

1 that the information and methods in Annex 1 should be adopted for the assessment of the propagation characteristics of short-range outdoor radio systems between 300 MHz and 100 GHz where applicable.

2 Rec. ITU-R P.1411-6

Annex 1

1 Introduction

Propagation over paths of length less than 1 km is affected primarily by buildings and trees, rather than by variations in ground elevation. The effect of buildings is predominant, since most short-path radio links are found in urban and suburban areas. The mobile terminal is most likely to be held by a pedestrian or located in a vehicle.

This Recommendation defines categories for short propagation paths, and provides methods for estimating path loss, delay spread and angular spread over these paths.

2 Physical operating environments and definition of cell types

Environments described in this Recommendation are categorized solely from the radio propagation perspective. Radiowave propagation is influenced by the environment, i.e. building structures and heights, the usage of the mobile terminal (pedestrian/vehicular) and the positions of the antennas. Four different environments are identified, considered to be the most typical. Hilly areas, for example, are not considered, as they are less typical in metropolitan areas. Table 1 lists the four environments. Recognizing that there is a wide variety of environments within each category, it is not intended to model every possible case but to give propagation models that are representative of environments frequently encountered.

TABLE 1

Physical operating environments – Propagation impairments

Environment Description and propagation impairments of concern

Urban very high-rise

– Busiest urban deep canyon, characterized by streets lined with high-density buildings with several tens of floors which results in an urban deep canyon

– High dense buildings and skyscrapers interleave with each other which yields to the rich scattering propagation paths in NLoS

– Rows of tall buildings provide the possibility of very long path delays– Heavy traffic vehicles and high flowrate visitors in the area act as reflectors

adding Doppler shift to the reflected waves– Trees beside the streets provide dynamic shadowing

Urban high-rise – Urban canyon, characterized by streets lined with tall buildings of several floors each

– Building height makes significant contributions from propagation over roof-tops unlikely

– Rows of tall buildings provide the possibility of long path delays– Large numbers of moving vehicles in the area act as reflectors adding Doppler

shift to the reflected wavesUrban/suburban low-rise

– Typified by wide streets– Building heights are generally less than three stories making diffraction over

roof-top likely– Reflections and shadowing from moving vehicles can sometimes occur– Primary effects are long delays and small Doppler shifts

Rec. ITU-R P.1411-6 3

TABLE 1 (end)

Environment Description and propagation impairments of concern

Residential – Single and double storey dwellings– Roads are generally two lanes wide with cars parked along sides– Heavy to light foliage possible– Motor traffic usually light

Rural – Small houses surrounded by large gardens– Influence of terrain height (topography)– Heavy to light foliage possible– Motor traffic sometimes high

For each of the four different environments two possible scenarios for the mobile are considered. Therefore the users are subdivided into pedestrian and vehicular users. For these two applications the velocity of the mobile is quite different yielding different Doppler shifts. Table 2 shows typical velocities for these scenarios.

TABLE 2

Physical operating environments – Typical mobile velocity

EnvironmentVelocity for

pedestrian users(m/s)

Velocity for vehicular users

Urban high-rise 1.5 Typical downtown speeds around 50 km/h (14 m/s)Urban/suburban low-rise 1.5 Around 50 km/h (14 m/s)

Expressways up to 100 km/h (28 m/s)Residential 1.5 Around 40 km/h (11 m/s)Rural 1.5 80-100 km/h (22-28 m/s)

The type of propagation mechanism that dominates depends also on the height of the base station antenna relative to the surrounding buildings. Table 3 lists the typical cell types relevant for outdoor short-path propagation.

TABLE 3

Definition of cell types

Cell type Cell radius Typical position of basestation antenna

Micro-cell 0.05 to 1 km Outdoor; mounted above average roof-top level, heights of some surrounding buildings may be above base station antenna height

Dense urban micro-cell

0.05 to 0.5 km Outdoor; mounted below average roof-top level

Pico-cell Up to 50 m Indoor or outdoor (mounted below roof-top level)

(Note that “dense urban micro-cell” is not explicitly defined in Radiocommunication Study Group 5 Recommendation.)

4 Rec. ITU-R P.1411-6

3 Path categories

3.1 Definition of propagation situations

Four situations of base station (BS) and mobile station (MS) geometries are depicted in Fig. 1. Base station BS1 is mounted above roof-top level. The corresponding cell is a micro-cell. Propagation from this BS is mainly over the roof-tops. Base station BS2 is mounted below roof-top level and defines a dense urban micro- or pico-cellular environment. In these cell types, propagation is mainly within street canyons. For mobile-to-mobile links, both ends of the link can be assumed to be below roof-top level, and the models relating to BS2 may be used.

3.1.1 Propagation over rooftops, non-line-of-sight (NLoS)

The typical NLoS case (link BS1-MS1 in Fig. 1) is described by Fig. 2. In the following, this case is called NLoS1.

FIGURE 1Typical propagation situation in urban areas

Rec. ITU-R P.1411-6 5

FIGURE 2Definition of parameters for the NLoS1 case

The relevant parameters for this situation are:hr : average height of buildings (m)

w : street width (m)b : average building separation (m) : street orientation with respect to the direct path (degrees)hb : BS antenna height (m)hm : MS antenna height (m)l : length of the path covered by buildings (m)d : distance from BS to MS.

The NLoS1 case frequently occurs in residential/rural environments for all cell-types and is predominant for micro-cells in urban/suburban low-rise environments. The parameters hr, b and l can be derived from building data along the line between the antennas. However, the determination of w and requires a two-dimensional analysis of the area around the mobile. Note that l is not necessarily normal to the building orientation.

3.1.2 Propagation along street canyons, NLoS

Figure 3 depicts the situation for a typical dense urban micro-cellular NLoS-case (link BS 2-MS3 in Fig. 1). In the following, this case is called NLoS2.

6 Rec. ITU-R P.1411-6

FIGURE 3Definition of parameters for the NLoS2 case

The relevant parameters for this situation are:w1 : street width at the position of the BS (m)w2 : street width at the position of the MS (m)x1 : distance BS to street crossing (m)x2 : distance MS to street crossing (m) : is the corner angle (rad).

NLoS2 is the predominant path type in urban high-rise environments for all cell-types and occurs frequently in dense urban micro- and pico-cells in urban low-rise environments. The determination of all parameters for the NLoS2 case requires a two-dimensional analysis of the area around the mobile.

3.1.3 Line-of-sight (LoS) paths

The paths BS1-MS2 and BS2-MS4 in Fig. 1 are examples of LoS situations. The same models can be applied for both types of LoS path.

3.2 Data requirements

For site-specific calculations in urban areas, different types of data can be used. The most accurate information can be derived from high-resolution data where information consists of:– building structures;– relative and absolute building heights;– vegetation information.

Data formats can be both raster and vector. The location accuracy of the vector data should be of the order of 1 to 2 m. The recommended resolution for the raster data is 1 to 10 m. The height accuracy for both data formats should be of the order of 1 to 2 m.

If no high-resolution data are available, low-resolution land-use data (50 m resolution) are recommended. Depending on the definition of land-use classes (dense urban, urban, suburban, etc.) the required parameters can be assigned to these land-use classes. These data can be used in conjunction with street vector information in order to extract street orientation angles.

Rec. ITU-R P.1411-6 7

4 Path loss models

For typical scenarios in urban areas some closed-form algorithms can be applied. These propagation models can be used both for site-specific and site-general calculations. The corresponding propagation situations are defined in § 3.1. The type of the model depends also on the frequency range. Different models have to be applied for UHF propagation and for mm-wave propagation. In the UHF frequency range LoS and NLoS situations are considered. In mm-wave propagation LoS is considered only. Additional attenuation by oxygen and hydrometeors has to be considered in the latter frequency range.

4.1 LoS situations within street canyons

UHF propagation

In the UHF frequency range, basic transmission loss, as defined by Recommendation ITU-R P.341, can be characterized by two slopes and a single breakpoint. An approximate lower bound is given by:

LLoS,l = Lbp + {20 log10 ( dRbp ) for d ≤ Rbp

40 log10 ( dRbp ) for d > Rbp

(1)

where Rbp is the breakpoint distance and is given by:

Rbp ≈4 hbhm

λ (2)

where is the wavelength (m). The lower bound is based on two-ray ground reflective model.

An approximate upper bound is given by:

LLoS,u = Lbp + 20 + {25 log10( dRbp ) for d ≤ Rbp

40 log10( dRbp ) for d > Rbp

(3)

Lbp is a value for the basic transmission loss at the break point, defined as:

Lbp = |20 log10( λ2

8 π hb hm)|

(4)

The upper bound has the fading margin of 20 dB. In equation (3), the attenuation coefficient before breakpoint is set to 2.5 because a short distance leads to weak shadowing effect.

8 Rec. ITU-R P.1411-6

According to the free-space loss curve, a median value is given by:

LLoS,m = Lbp +6+ {20 log10( dRbp ) for d ≤ Rbp

40 log10( dRbp ) for d > Rbp

(5)

SHF propagation up to 15 GHz

At SHF, for path lengths up to about 1 km, road traffic will influence the effective road height and will thus affect the breakpoint distance. This distance, Rbp, is estimated by:

Rbp = 4(hb−hs ) (hm−hs )

λ (6)

where hs is the effective road height due to such objects as vehicles on the road and pedestrians near the roadway. Hence hs depends on the traffic on the road. The hs values given in Tables 4 and 5 are derived from daytime and night-time measurements, corresponding to heavy and light traffic conditions, respectively. Heavy traffic corresponds to 10-20% of the roadway covered with vehicles, and 0.2-1% of the footpath occupied by pedestrians. Light traffic was 0.1-0.5% of the roadway and less than 0.001% of the footpath occupied. The roadway was 27 m wide, including 6 m wide footpaths on either side.

TABLE 4

The effective height of the road, hs (heavy traffic)

Frequency(GHz)

hb(m)

hs(m)

hm 2.7 hm 1.6

3.354 1.3 (2)

8 1.6 (2)

8.454 1.6 (2)

8 1.6 (2)

15.754 1.4 (2)

8 (1) (2)

(1) The breakpoint is beyond 1 km.(2) No breakpoint exists.

Rec. ITU-R P.1411-6 9

TABLE 5

The effective height of the road, hs (light traffic)

Frequency(GHz)

hb(m)

hs(m)

hm 2.7 hm 1.6

3.354 0.59 0.238 (1) (1)

8.454 (2) 0.43

8 (2) (1)

15.754 (2) 0.74

8 (2) (1)

(1) No measurements taken.(2) The breakpoint is beyond 1 km.

When hm  hs, the approximate values of the upper and lower bounds of basic transmission loss for the SHF frequency band can be calculated using equations (1) and (3), with Lbp given by:

Lbp = |20 log10{ λ2

8 π (hb − hs) ( hm − hs )}|(7)

On the other hand, when hm  hs no breakpoint exists. The area near the BS (d  Rs) has a basic propagation loss similar to that of the UHF range, but the area distant from the BS has propagation characteristics in which the attenuation coefficient is cubed. Therefore, the approximate lower bound for d  Rs is given by:

LLoS , l = Ls + 30 log10 ( dRs )

(8)

The approximate upper bound for d  Rs is given by:

LLoS , u = Ls +20 +30 log10 ( dR s ) (9)

The basic propagation loss Ls is defined as:

Ls = |20 log10 ( λ2 πR s )|

(10)

Rs in equations (8) to (10) has been experimentally determined to be 20 m.

Based on measurements, a median value is given by:

10 Rec. ITU-R P.1411-6

LLoS ,m = Ls + 6 +30 log10 ( dRs )

(11)

Millimetre-wave propagation

At frequencies above about 10 GHz, the breakpoint distance Rbp in equation (2) is far beyond the expected maximum cell radius (500 m). This means that no fourth-power law is expected in this frequency band. Hence the power distance decay-rate will nearly follow the free-space law with a path-loss exponent of about 2.2. Attenuation by atmospheric gases and by rain must also be considered.

Gaseous attenuation can be calculated from Recommendation ITU-R P.676, and rain attenuation from Recommendation ITU-R P.530.

4.2 Models for NLoS situations

NLoS signals can arrive at the BS or MS by diffraction mechanisms or by multipath which may be a combination of diffraction and reflection mechanisms. This section develops models that relate to diffraction mechanisms.

Propagation for urban area

Models are defined for the two situations described in § 3.1. The models are valid for:hb: 4 to 50 mhm: 1 to 3 mf: 800 to 5 000 MHz

2 to 16 GHz for hb < hr and w2 < 10 m (or sidewalk)d: 20 to 5 000 m.

(Note that although the model is valid up to 5 km, this Recommendation is intended for distances only up to 1 km.)

Propagation for suburban area

Model is defined for the situation of hb > hr described in § 3.1. The model is valid for:hr: any height mhb: 1 to 100 mhm: 4 to 10 (less than hr) mhb: hr + hb mhm: hr − hm mf: 0.8 to 20 GHzw: 10 to 25 md: 10 to 5 000 m

(Note that although the model is valid up to 5 km, this Recommendation is intended for distances only up to 1 km.)

Millimetre-wave propagation

Millimetre-wave signal coverage is considered only for LoS situations because of the large diffraction losses experienced when obstacles cause the propagation path to become NLoS. For NLoS situations, multipath reflections and scattering will be the most likely signal propagation method.

Rec. ITU-R P.1411-6 11

4.2.1 Propagation over roof-tops for urban area

The multi-screen diffraction model given below is valid if the roof-tops are all about the same height. Assuming the roof-top heights differ only by an amount less than the first Fresnel-zone radius over a path of length l (see Fig. 2), the roof-top height to use in the model is the average roof-top height. If the roof-top heights vary by much more than the first Fresnel-zone radius, a preferred method is to use the highest buildings along the path in a knife-edge diffraction calculation, as described in Recommendation ITU-R P.526, to replace the multi-screen model.

In the model for transmission loss in the NLoS1-case (see Fig. 2) for roof-tops of similar height, the loss between isotropic antennas is expressed as the sum of free-space loss, Lbf, the diffraction loss from roof-top to street Lrts and the reduction due to multiple screen diffraction past rows of buildings, Lmsd.

In this model Lbf and Lrts are independent of the BS antenna height, while Lmsd is dependent on whether the base station antenna is at, below or above building heights.

LNLoS1 = {Lbf + Lrts + Lmsd for Lrts + Lmsd > 0Lbf for Lrts + Lmsd ≤ 0

(12)

The free-space loss is given by:

Lbf = 32. 4 + 20 log10 (d / 1 000) + 20 log10 ( f ) (13)

where:d : path length (m)f : frequency (MHz).

The term Lrts describes the coupling of the wave propagating along the multiple-screen path into the street where the mobile station is located. It takes into account the width of the street and its orientation.

Lrts = – 8 .2 – 10 log10 (w ) + 10 log10 ( f ) + 20 log10 ( Δhm) + Lori (14)

Lori = {–10 + 0 .354 ϕ for 0° ≤ ϕ < 35°2.5 + 0 . 075( ϕ – 35) for 35 ° ≤ ϕ < 55 °4 .0 – 0 . 114(ϕ – 55 ) for 55 ° ≤ ϕ ≤ 90 °

(15)

where:

Δhm = hr – hm (16)

Lori is the street orientation correction factor, which takes into account the effect of roof-top-to-street diffraction into streets that are not perpendicular to the direction of propagation (see Fig. 2).

The multiple screen diffraction loss from the BS due to propagation past rows of buildings depends on the BS antenna height relative to the building heights and on the incidence angle. A criterion for grazing incidence is the “settled field distance”, ds:

12 Rec. ITU-R P.1411-6

d s = λd2

Δhb2

(17)

where (see Fig. 2):

Δhb = hb – hr (18)

For the calculation of Lmsd, ds is compared to the distance l over which the buildings extend. The calculation for Lmsd uses the following procedure to remove any discontinuity between the different models used when the length of buildings is greater or less than the “settled field distance”.

The overall multiple screen diffraction model loss is given by:

Lmsd=¿ {− tanh(log ( d )−log (dbp )χ )⋅( L1msd (d )−Lmid )+Lmid for l>ds and dhbp>0¿ { ¿ {tanh( log ( d )−log (dbp )

χ )⋅( L2msd ( d )−Lmid )+Lmid for l≤ds and dhbp>0 ¿ {L2msd (d ) for dhbp=0¿ {L1msd (d )−tanh( log ( d )−log (dbp )ζ )⋅(Lupp−Lmid )−Lupp+Lmid for l>d s and dhbp<0 ¿ { ¿¿¿ ¿

(19)

where:

dhbp=Lupp−Llow (20)

ζ =( Lupp−Llow)⋅υ (21)

Lmid=( Lupp+Llow )

2 (22)

Lupp=L1msd (dbp ) (23)

Llow=L2msd ( dbp) (24)

and

dbp =|Δhb|√ lλ (25)

= [0.0417]

Rec. ITU-R P.1411-6 13

= [0.1]

where the individual model losses, L1msd (d) and L2msd (d), are defined as follows:

Calculation of L1msd for l  ds

(Note this calculation becomes more accurate when l  ds.)

L 1msd (d ) = Lbsh + k a + kd log10 ( d / 1 000 ) + k f log10 ( f ) − 9 log10 (b ) (26)

where:

Lbsh = {– 18 log10(1 + Δhb ) for hb > hr

0 for hb ≤ hr (27)

is a loss term that depends on the BS height:

k a={71 . 4 for hb> hr and f > 2 000 MHz73−0 . 8 Δhb for hb≤ hr , f > 2 000 MHz and d ≥ 500 m73−1. 6 Δhb d /1 000 for hb≤ hr , f > 2 000 MHz and d < 500 m54 for hb> hr and f ≤ 2 000 MHz54−0 . 8 Δhb for hb≤ hr , f ≤ 2 000 MHz and d ≥ 500 m54−1 .6 Δhb d /1 000 for hb≤ hr , f ≤ 2 000 MHz and d < 500 m

(28)

k d = {18 for hb > hr

18 – 15Δhb

hrfor hb ≤ hr

(29)

k f = ¿ {−8 for f >2 000 MHz ¿¿¿(30)

Calculation of L2msd for l  ds

In this case a further distinction has to be made according to the relative heights of the BS and the roof-tops:

L 2msd (d ) = –10 log10 (QM2 ) (31)

where:

14 Rec. ITU-R P.1411-6

QM = { 2.35 ( Δhb

d √ bλ )

0 .9

for hb > hr+δhu

bd

for hb ≤ hr +δhu and hb ≥ hr +δhl

b2πd √ λ

ρ ( 1θ

– 12 π + θ ) for hb < hr+δhl

(32)

and

θ = arctan ( Δhb

b )(33)

ρ = √ Δhb2 + b2

(34)

and δhu = 10−log10(√ b

λ ) −log10 ( d )

9+

109

log10( b2 . 35 )

(35)

δhl = 0.00023 b2−0 . 1827 b−9 . 4978

( log10 (f ) )2.938 +0.000781 b+0 .06923(36)

4.2.2 Propagation over roof-tops for suburban area

A propagation model for the NLoS1-Case based on geometrical optics (GO) is shown in Fig. 2. This figure indicates that the composition of the arriving waves at the MS changes according to the BS-MS distance. A direct wave can arrive at the MS only when the BS-MS distance is very short. The several-time (one-, two-, or three-time) reflected waves, which have a relatively strong level, can arrive at the MS when the BS-MS separation is relatively short. When the BS-MS separation is long, the several-time reflected waves cannot arrive and only many-time reflected waves, which have weak level beside that of diffracted waves from building roofs, arrive at the MS. Based on these propagation mechanisms, the loss due to the distance between isotropic antennas can be divided into three regions in terms of the dominant arrival waves at the MS. These are the direct wave, reflected wave, and diffracted wave dominant regions. The loss in each region is expressed as follows based on GO.

LNLoS 1={20⋅log10( 4 πdλ ) for d < d0 (Direct wave dominant region )

L0 n for d0 ≤ d<dRD (Reflected wave dominant region )

32 .1⋅log10( ddRD )+LdRD

for d≥dRD (Diffracted wave dominant region )

(37)

Rec. ITU-R P.1411-6 15

where:

L0 n={Ldk+

Ld k+1−Ldk

dk+1−dk¿ (d−dk ) when dk ¿d<dk+1 ¿dRD

( k=0 , 1 , 2. .. )

Ld k+

Ld RD−Ldk

d RD−dk¿ ( d−dk ) when dk ¿d<dRD ¿dk +1

(38)

dk=1

sin ϕ⋅√B

k2+( hb−hm)2(39)

Ldk=20⋅log10{ 4 πdkp

0 . 4k ¿ λ }(40)

d RD ( f )=0 .625⋅( d3−d1)⋅log10 ( f )+0 . 44⋅d1+0 .5⋅d2+0.06⋅d3

( 0. 8 GHz ≤f ≤ 20 GHz ) (41)

LdRD=Ldk

+Ldk +1

−Ldk

dk +1−dk¿ ( dRD−dk ) ( dk ¿d RD ¿dk+1 )

(42)

dkp= 1sin ϕk

⋅√ Ak2+( hb−hm )2

(43)

Ak=w⋅(hb−hm )⋅(2k+1 )

2⋅(hr−hm ) (44)

Bk=w⋅( hb−hm )⋅(2 k+1 )

2⋅( hr−hm)−k⋅w

(45)

ϕk= tan−1( Bk

Ak⋅tan ϕ)

(46)

4.2.3 Propagation within street canyons for frequency range from 800 to 2 000 MHz

For NLoS2 situations where both antennas are below roof-top level, diffracted and reflected waves at the corners of the street crossings have to be considered (see Fig. 3).

LNLoS 2=−10 log10 (10− Lr/10+10

−Ld /10 )                 dB (47)

where:Lr : reflection path loss defined by:

16 Rec. ITU-R P.1411-6

Lr=20 log10 (x1+ x2 )+x1 x2f (α )w1w2

+20 log10( 4 πλ )

                dB (48)

where:

f (α ) = 3 .86α3. 5

                dB (49)

where 0.6 < [rad] < .Ld : diffraction path loss defined by:

Ld=10 log10 [ x1 x2( x1+x2 )]+2 Da−0. 1(90−α 180π )+20 log10( 4 π

λ )                dB (50)

Da = (402π ) [arctan( x2

w2) + arctan( x1

w1 ) – π2 ]

                dB (51)

4.2.4 Propagation within street canyons for frequency range from 2 to 16 GHz

The propagation model for the NLoS2 situations as described in § 3.1.2 with the corner angle  = /2 rad is derived based on measurements at a frequency range from 2 to 16 GHz, where hb < hr

and w2 is up to 10 m (or sidewalk). The path loss characteristics can be divided into two parts: the corner loss region and the NLoS region. The corner loss region extends for dcorner from the point which is 1 m down the edge of the LoS street into the NLoS street. The corner loss (Lcorner) is expressed as the additional attenuation over the distance dcorner. The NLoS region lies beyond the corner loss region, where a coefficient parameter () applies. This is illustrated by the typical curve shown in Fig. 4. Using x1, x2, and w1, as shown in Fig. 3, the overall path loss (LNLoS2) beyond the corner region (x2 > w1/2 + 1) is found using:

LNLoS 2=LLos+ Lc+Latt (52)

Lc={ Lcorner

log10 (1+ d corner )log10 ( x2−w1 /2 ) w1/2+1 <x2≤w1/2+1+ d corner

Lcorner x2>w1/2+1+ d corner (53)

Latt ={10 β log10( x1+x2

x1+w1 /2+ d corner ) x2>w1/2+1+ d corner

0 x2>w1/2+1+ d corner (54)

where LLoS is the path loss in the LoS street for x1 (> 20 m), as calculated in § 4.1. In equation (53), Lcorner is given as 20 dB in an urban environment and 30 dB in a residential environment. And dcorner

is 30 m in both environments. In equation (54), is given by 6 in both environments.

Rec. ITU-R P.1411-6 17

FIGURE 4Typical trend of propagation along street canyons with low base station height

for frequency range from 2 to 16 GHz

In a residential environment, the path loss does not increase monotonically with distance, and thus the coefficient parameter may be lower than the value in an urban environment, owing to the presence of alleys and gaps between the houses.

With a high base station antenna in the small macro-cell, the effects of diffraction over roof-tops are more significant. Consequently, the propagation characteristics do not depend on the corner loss.

4.3 Propagation between terminals located below roof-top height at UHF

The model described below is intended for calculating the basic transmission loss between two terminals of low height in urban environments. It includes both LoS and NLoS regions, and models the rapid decrease in signal level noted at the corner between the LoS and NLoS regions. The model includes the statistics of location variability in the LoS and NLoS regions, and provides a statistical model for the corner distance between the LoS and NLoS regions. Figure 5 illustrates the LoS, NLoS and corner regions, and the statistical variability predicted by the model.

This model is recommended for propagation between low-height terminals where both terminal antenna heights are near street level well below roof-top height, but are otherwise unspecified. It is reciprocal with respect to transmitter and receiver and is valid for frequencies in the range 300-3 000 MHz. The model is based on measurements made in the UHF band with antenna heights between 1.9 and 3.0 m above ground, and transmitter-receiver distances up to 3 000 m.

18 Rec. ITU-R P.1411-6

FIGURE 5Curves of basic transmission loss not exceeded for 1, 10, 50, 90 and 99% of locations

(frequency = 400 MHz, suburban)

The parameters required are the frequency f (MHz) and the distance between the terminals d (m).Step 1: Calculate the median value of the line-of-sight loss:

LLoSmedian (d )=32 . 45+20 log10 f +20 log10(d /1 000 ) (55)

Step 2: For the required location percentage, p (%), calculate the LoS location correction:

ΔLLoS( p )=1 .5624 σ ( √−2 ln (1− p/100)−1. 1774 ) with  = 7 dB (56)

Alternatively, values of the LoS correction for p = 1, 10, 50, 90 and 99% are given in Table 6.

Step 3: Add the LoS location correction to the median value of LoS loss:

LLoS(d , p )=LLoSmedian( d )+ΔLLoS( p) (57)

Step 4: Calculate the median value of the NLoS loss:

LNLoSmedian (d )=9. 5+45 log10 f +40 log10(d /1 000 )+Lurban (58)

Lurban depends on the urban category and is 0 dB for suburban, 6.8 dB for urban and 2.3 dB for dense urban/high-rise.

Step 5: For the required location percentage, p (%), add the NLoS location correction:

ΔLNLoS( p )=σN−1 ( p /100) with  = 7 dB (59)N1(.) is the inverse normal cumulative distribution function. An approximation to this function, good for p between 1 and 99% is given by the location variability function Qi(x)

Rec. ITU-R P.1411-6 19

of Recommendation ITU-R P.1546. Alternatively, values of the NLoS location correction for p = 1, 10, 50, 90 and 99% are given in Table 6.

TABLE 6

Table of LoS and NLoS location variability corrections

p (%)

LLoS (dB)

LNLoS (dB)

dLoS (m)

1 –11.3 –16.3 97610 –7.9 –9.0 27650 0.0 0.0 4490 10.6 9.0 1699 20.3 16.3 10

Step 6: Add the NLoS location correction to the median value of NLoS loss:

LNLoS(d , p )=LNLoSmedian( d )+ΔLNLoS( p) (60)

Step 7: For the required location percentage, p (%), calculate the distance dLoS for which the LoS fraction FLoS equals p:

d LoS( p )=212 [ log10( p /100 )]2−64 log10( p/100) if p<45d LoS( p )=79 .2−70( p /100 ) otherwise (61)

Values of dLoS for p = 1, 10, 50, 90 and 99% are given in Table 6. This model has not been tested for p < 0.1%. The statistics were obtained from two cities in the United Kingdom and may be different in other countries. Alternatively, if the corner distance is known in a particular case, set dLoS(p) to this distance.

Step 8: The path loss at the distance d is then given as:a) If d < dLoS, then L(d, p) = LLoS(d, p)b) If d > dLoS + w, then L(d, p) = LNLoS(d, p)c) Otherwise linearly interpolate between the values LLoS(dLoS, p) and LNLoS(dLoS + w, p):

LLoS=LLoS(dLoS , p )LNLoS=LNLoS(dLoS+w , p )L(d , p )=LLoS+( LNLoS−LLoS)(d−dLoS )/w

The width w is introduced to provide a transition region between the LoS and NLoS regions. This transition region is seen in the data and typically has a width of w = 20 m.

4.4 Default parameters for site-general calculations

If the data on the structure of buildings and roads are unknown (site-general situations), the following default values are recommended:

hr   3 (number of floors) roof-height (m)

20 Rec. ITU-R P.1411-6

roof-height   3 m for pitched roofs  = 0 m for flat roofs

w  = b/2b  = 20 to 50 m  = 90.

4.5 Influence of vegetation

The effects of propagation through vegetation (primarily trees) are important for outdoor short-path predictions. Two major propagation mechanisms can be identified: – propagation through (not around or over) trees;– propagation over trees.

The first mechanism predominates for geometries in which both antennas are below the tree tops and the distance through the trees is small, while the latter predominates for geometries in which one antenna is elevated above the tree tops. The attenuation is strongly affected by multipath scattering initiated by diffraction of the signal energy both over and through the tree structures. For propagation through trees, the specific attenuation in vegetation can be found in Recommendation ITU-R P.833. In situations where the propagation is over trees, diffraction is the major propagation mode over the edges of the trees closest to the low antenna. This propagation mode can be modelled most simply by using an ideal knife-edge diffraction model (see Recommendation ITU-R P.526), although the knife-edge model may underestimate the field strength, because it neglects multiple scattering by tree-tops, a mechanism that may be modelled by radiative transfer theory.

5 Building entry loss

Building entry loss is the excess loss due to the presence of a building wall (including windows and other features). It is defined as the difference between the signal levels outside and inside the building at the same height. Account must also be taken of the incident angle. (When the path length is less than about 10 m, the difference in free space loss due to the change in path length for the two measurements should be taken into account in determining the building entry loss. For antenna locations close to the wall, it may also be necessary to consider near-field effects.) Additional losses will occur for penetration within the building; advice is given in Recommendation ITU-R P.1238. It is believed that, typically, the dominant propagation mode is one in which signals enter a building approximately horizontally through the wall surface (including windows), and that for a building of uniform construction the building entry loss is independent of height.

Building entry loss should be considered when evaluating the radio coverage from an outdoor system to an indoor terminal. It is also important for considering interference problems between outdoor systems and indoor systems.

The experimental results shown in Table 7 were obtained at 5.2 GHz through an external building wall made of brick and concrete with glass windows. The wall thickness was 60 cm and the window-to-wall ratio was about 2:1.

Rec. ITU-R P.1411-6 21

TABLE 7

Example of building entry loss

Frequency Residential Office Commercial

Mean Standard deviation Mean Standard

deviation Mean Standard deviation

5.2 GHz 12 dB 5 dB

Table 8 shows the results of measurements at 5.2 GHz through an external wall made of stone blocks, at incident angles from 0 to 75. The wall was 400 mm thick, with two layers of 100 mm thick blocks and loose fill between. Particularly at larger incident angles, the loss due to the wall was extremely sensitive to the position of the receiver, as evidenced by the large standard deviation.

TABLE 8

Loss due to stone block wall at various incident angles

Incident angle (degrees) 0 15 30 45 60 75Loss due to wall (dB) 28 32 32 38 45 50Standard deviation (dB) 4 3 3 5 6 5

Additional information on building entry loss, intended primarily for satellite systems, can be found in Recommendation ITU-R P.679 and may be appropriate for the evaluation of building entry for terrestrial systems.

6 Multipath models

A description of multipath propagation and definition of terms are provided in Recommendation ITU-R P.1407.

6.1 Multipath models for street canyon environments

6.1.1 Omnidirectional antenna case

Characteristics of multipath delay spread for the LoS omnidirectional antenna case in an urban high-rise environment for dense urban micro-cells and pico-cells (as defined in Table 3) have been developed based on measured data at frequencies from 2.5 to 15.75 GHz at distances from 50 to 400 m. The r.m.s. delay spread S at distance of d m follows a normal distribution with the mean value given by:

as=Ca dγa

                ns (62)

and the standard deviation given by:

σ s=Cσ dγσ

                ns (63)

22 Rec. ITU-R P.1411-6

where Ca, a, C and depend on the antenna height and propagation environment. Table 9 lists some typical values of the coefficients for distances of 50-400 m based on measurements made in urban and residential areas.

TABLE 9

Typical coefficients for the distance characteristics of r.m.s. delay spreadfor omnidirectional antenna case

Measurement conditions as s

Area f(GHz)

hb

(m)hm

(m) Ca a C

Urban(1) 0.781 5 5 1 254.3 0.06 102.2 0.04

Urban(2)

2.5 6.0 3.0 55 0.27 12 0.32

3.35-15.754.0

2.7 23 0.26 5.5 0.351.6

10 0.51 6.1 0.393.35-8.45 0.5

Residential(2)3.35

4.02.7 2.1 0.53 0.54 0.77

3.35-15.75 1.6 5.9 0.32 2.0 0.48(1) Threshold value of 20 dB is used for r.m.s. delay spread calculation.(2) Threshold value of 30 dB is used for r.m.s. delay spread calculation.

From the measured data at 2.5 GHz, the average shape of the delay profile was found to be:

P( t ) = P0 + 50 ( e– t /τ – 1 )                dB (64)

where:P0 : peak power (dB) : decay factor

and t is in ns.

From the measured data, for an r.m.s. delay spread S, can be estimated as:

τ = 4 S + 266                 ns (65)

A linear relationship between and S is only valid for the LoS case.

From the same measurement set, the instantaneous properties of the delay profile have also been characterized. The energy arriving in the first 40 ns has a Rician distribution with a K-factor of about 6 to 9 dB, while the energy arriving later has a Rayleigh or Rician distribution with a K-factor of up to about 3 dB. (See Recommendation ITU-R P.1057 for definitions of probability distributions.)

6.1.2 Directional antenna case

In fixed wireless access systems and communications between the access points of wireless mesh network systems, directional antennas are employed as transmitter and receiver antennas. A typical

Rec. ITU-R P.1411-6 23

effect of the use of directional antennas is given hereafter. Arriving delayed waves are suppressed by the antenna pattern using directional antennas as the transmitter and receiver antennas. Therefore, the delay spread becomes small. In addition, the received power increases with the antenna gain, when directional antennas are employed as the transmitter and receiver antennas. Based on these facts, the directional antenna is used in wireless systems. Therefore, it is important to understand the effect of antenna directivity in multipath models.

Characteristics of the multipath delay spread for the LoS directional antenna case in an urban high-rise environment for dense urban micro-cells and pico-cells (as defined in Table 3) were developed based on measured data in the 5.2 GHz band at distances from 10 to 500 m. The antennas were configured such that the direction of the maximum antenna gain of one antenna faced that of the other. Table 10 lists equation for deriving coefficients relative to the antenna half power beamwidth for formula (58) for distances of 10-500 m based on measurements in an urban area. These equations are only depending on the antenna half power beamwidth and effective to any width of the road.

TABLE 10

Typical coefficients for the distance characteristics of r.m.s. delay spreadfor directional antenna case

Measurement conditions as

Area f(GHz)

hb

(m)hm

(m) Ca a

Urban 5.2 3.5 3.5 9.3 + 1.5log() 3.3 × 10−2 + 4.6θ × 10−2

NOTE 1 – Threshold value of 20 dB is used for r.m.s. delay spread calculation.

Here, θ represents antenna half-power beamwidth at both transmitting and receiving antenna and the unit is radian. Note that θ should be set to 2π when omnidirectional antenna is applied to both transmitting and receiving antenna.

6.2 Multipath models for over-rooftops propagation environments

Characteristics of multipath delay spread for both LoS and NLoS case in an urban high-rise environment for micro-cells (as defined in Table 3) have been developed based on measured data at 1 920-1 980 MHz, 2 110-2 170 MHz, and 3 650-3 750 MHz using omnidirectional antennas. The median r.m.s. delay spread S in this environment is given by:

Su=exp ( A⋅L+B )                 ns (66)

where both A and B are coefficients of r.m.s. delay spread and L is path loss (dB). Table 11 lists the typical values of the coefficients for distances of 100 m – 1 km based on measurements made in urban areas.

TABLE 11

Typical coefficients for r.m.s. delay spread

Measurement conditions Coefficients of r.m.s. delay spread

Area Frequency(GHz)

Range(m) A B

24 Rec. ITU-R P.1411-6

Urban3 650-3 750 MHz 100-1 000 0.031 2.0911 920-1 980 MHz,2 110-2 170 MHz 100-1 000 0.038 2.3

The distributions of the multipath delay characteristics for the 3.7 GHz band in an urban environment with each BS antenna height of 40 m and 60 m, and MS antenna height of 2 m were derived from measurements. The distributions of the multipath delay characteristics for the 3.7 GHz and 5.2 GHz band in a suburban environment with a BS antenna height of 20 m, and MS antenna height of 2.0 m and 2.8 m were derived from measurements. Table 12 lists the measured r.m.s. delay spread for the 3.7 GHz and 5.2 GHz band for cases where the cumulative probability is 50% and 95%.

TABLE 12

Typical r.m.s. delay spread values*

Measurement conditions r.m.s. delay spread(ns)

Area Scenario Frequency(GHz)

Antenna heightRange

(m) 50% 95%hBS

(m)hr

(m)

Urban very high-rise

LoS2.5 100 2 100-1 000

208 461NLoS 407 513

Urban 3.760 2 100-1 000 232 40840 2 100-1 000 121 357

Suburban3.7 20 2 100-1 000 125 5425.2 20 2.8 100-1 000 189 577

* Threshold value of 30 dB was used for r.m.s. delay spread calculation.

7 Number of signal components

For the design of high data rate systems with multipath separation and synthesis techniques, it is important to estimate the number of signal components (that is, a dominant component plus multipath components) arriving at the receiver. The number of signal components can be represented from the delay profile as the number of peaks whose amplitudes are within A dB of the highest peak and above the noise floor, as shown in Fig. 6.

Rec. ITU-R P.1411-6 25

FIGURE 6Definition for the determination of the number of peaks

Table 13 shows the results for the number of signal components from measurements in different scenarios for different antenna heights, environments and for different frequencies.

TABLE 13

Maximum number of signal components

Type of environment

Time delay

resolution

Frequency(GHz)

Antenna height

(m)

Range(m) Maximum number of components

hb hm 3 dB 5 dB 10 dB

80% 95% 80% 95% 80% 95%

Urban 200 ns 1.9-2.1 46 1.7 100-1 600 1 2 1 2 2 4

Suburban 175 ns 2.5 12 1 200-1 500 1 2 1 2 2 4Urban 20 ns 3.35 4

55

1.6

2.7

0-2000-1 000150-590

222

332

222

443

553

6913

Residential 20 ns 3.35 4 2.7 0-480 2 2 2 2 2 3Suburban 175 ns 3.5 12 1 200-1 500 1 2 1 2 1 5

Suburban 50 ns 3.67 40 2.7 0-5 000 1 2 1 3 3 5Suburban 100 ns 5.8 12 1 200-1 500 1 2 3 5 4 5

Urban 20 ns 8.45 4

55

1.6

2.7

0-2000-1 000150-590

112

322

222

343

443

6812

Urban 20 ns 15.75 4 1.6 0-2000-1 000

12

33

22

34

46

510

26 Rec. ITU-R P.1411-6

For the measurements described in § 6.2, the differential time delay window for the strongest 4 components with respect to the first arriving component and their relative amplitude is given in Table 15.

8 Polarization characteristics

Cross-polarization discrimination (XPD), as defined in Recommendation ITU-R P.310, differs between LoS and NLoS areas in an SHF dense urban micro-cellular environment. Measurements indicate a median XPD of 13 dB for LoS paths and 8 dB for NLoS paths, and a standard deviation of 3 dB for LoS paths and 2 dB for NLoS paths at SHF. These median values are compatible with the UHF values for open and urban areas, respectively, in Recommendation ITU-R P.1406.

Rec. ITU-R P.1411-6 27

TABLE 14

Type of environment

BSantenna

Frequency(GHz)

Antenna height(m)

Range(m) Maximum number of signal components

hb hm A = 3 dB A = 5 dB A = 10 dB80% 95% 80% 95% 80% 95%

Urban Low 3.35 4 1.6 0-200 2 3 2 4 5 60-1 000 2 3 2 4 5 9

Urban Low 8.45 4 1.6 0-200 1 3 2 3 4 60-1 000 1 2 2 4 4 8

Urban Low 15.75 4 1.6 0-200 1 3 2 3 4 50-1 000 2 3 2 4 6 10

Urban High 3.35 55 2.7 150-590 2 2 2 3 3 138.45 55 2.7 150-590 2 2 2 3 3 12

Residential Low 3.35 4 2.7 0-480 2 2 2 2 2 3Suburban High 3.67 40 2.7 0-5 000 1 2 1 3 3 5

TABLE 15

Differential time delay window for the strongest 4 components with respect to the first arriving componentand their relative amplitude

Type of environment

Time delay resolution

Frequency (GHz)

Antenna height (m)

Range(m)

Excess time delay (s)

hb hm 1st 2nd 3rd 4th

80% 95% 80%

95% 80%

95% 80%

95%

Urban 200 ns 1.9-2.1 46 1.7 100-1 600 0.5 1.43 1.1 1.98 1.74 2.93 2.35 3.26Relative power with respect to strongest component (dB) 0 0 −7.3 −9 −8.5 −9.6 −9.1 −9.8

28 Rec. ITU-R P.1411-6

Rec. ITU-R P.1411-6 29

9 Characteristics of direction of arrival

The r.m.s. angular spread as defined in Recommendation ITU-R P.1407 in the azimuthal direction in a dense urban micro-cell or picocell environment in an urban area was obtained from the measurement made at a frequency of 8.45 GHz. The receiving base station had a parabolic antenna with a half-power beamwidth of 4°.

Also measurement performed at the dense urban micro-cell environment in urban area. Angular spread coefficients are introduced based on measurements in urban areas for distances of 10~1 000 m, under the LoS cases at a frequency of 0.781 GHz. Four elements omnidirectional linear array with Bartlett beam-forming method is used for deriving the angular profile.

The coefficients for r.m.s. angular spread were obtained as shown in Table 16.

TABLE 16

Typical coefficients for the distance characteristics of angular spread

Measurement conditionsMean

(degree)s.t.d

(degree) RemarkArea f

(GHz)hb

(m)hm

(m)

Urban 0.781 5 1.5 28.15 13.98 LoSUrban 8.45 2.7 4.4 30 11 LoSUrban 8.45 2.7 4.4 41 18 NLoS

10 Fading characteristics

The fading depth, which is defined as the difference between the 50% value and the 1% value in the cumulative probability of received signal levels, is expressed as a function of the product (2fLmax MHz·m) of the received bandwidth 2f MHz and the maximum difference in propagation path lengths Lmax m as shown in Fig. 7. Lmax is the maximum difference in propagation path lengths between components whose level is larger than the threshold, which is 20 dB lower than the highest level of the indirect waves as shown in Fig. 8. In this figure, a in decibels is the power ratio of the direct to the sum of indirect waves, and a = − dB represents a NLoS situation. When 2fLmax is less than 10 MHz·m, the received signal levels in LoS and NLoS situations follow Rayleigh and Nakagami-Rice distributions, corresponding to a narrow-band fading region. When it is larger than 10 MHz·m, it corresponds to a wideband fading region, where the fading depth becomes smaller and the received signal levels follow neither Rayleigh nor Nakagami-Rice distributions.

30 Rec. ITU-R P.1411-6

FIGURE 7Relationship between fading depth and 2fLmax

FIGURE 8Model for calculating Lmax

11 Propagation data and prediction methods for the path morphology approach

11.1 Classification of path morphology

In the populating area except rural area, the path morphology for wireless channels can be classified into 9 categories as shown in Table 17. The classification is fully based on real wave-propagation environment, by analysing building height and density distribution for various representative locations using GIS (Geographic Information System) database.

Rec. ITU-R P.1411-6 31

TABLE 17

Classification of path morphologies for the MIMO channel

Path morphology density

High rise(above 25 m)

High density (HRHD) above 35%Middle density (HRMD) 20 ~ 35%

Low density (HRLD) below 20%

Middle rise(12 m ~ 25 m)

High density (HRHD) above 35%Middle density (HRMD) 20 ~ 35%

Low density (HRLD) below 20%

Low rise(below 12 m)

High density (HRHD) above 35%Middle density (HRMD) 20 ~ 35%

Low density (HRLD) below 20%

11.2 Statistical modelling method

Usually the measurement data are very limited and not comprehensive. Therefore, for specific morphologies and specific operating frequencies, the following method can be used to derive the parameters for the MIMO channel model. Measurements of channel characteristics for 9 typical morphologies at 3.705 GHz have shown good statistical agreement when compared against modelling method.

Models are defined for the situation of hb hr. Definitions of the parameters f, d, hr, hb, hb and hm

are described in § 3.1, and Bd represents building density. The path morphology approach is valid for:f: 800 to 6 000 MHzd: 100 to 800 mhr: 3 to 60 mhb: hr + hb hb: up to 20 mhm: 1 to 3 mBd: 10 to 45%

In the statistical modelling, the buildings are generated in a fully random fashion. It is well known that the distribution of building height h is well fitted statistically by Rayleigh distribution P(h) with the parameter .

P(h )= hμ2 exp(−h2

2 μ2 ) (67)

To derive the statistical parameters of Rayleigh distribution for given morphology, the use of available GIS database is recommended. For the horizontal positions of buildings, it can be assumed to be uniformly distributed.

The wave-propagation calculation is performed for each realization of building distribution using the ray tracing method. 15 times reflection and 2 times diffraction are recommended for simulation. Penetration though buildings are also important. It is recommended to set up the receiving power threshold properly to consider the building penetration. To obtain the model parameters, simulations

32 Rec. ITU-R P.1411-6

should be performed for enough number of realizations for each morphology. At least 4 times realization is recommended. For each realization, enough number of receivers should be put in the calculation region, in order to obtain statistically meaningful data. It is recommended that at least 50 receivers are available at each 10 m sub-interval of distance. The transmitting antenna height and the receiving antenna should be set at the appropriate values. It is recommended that the values of dielectric constant and conductivity are set at r = 7.0, = 0.015 S/m for buildings, and r = 2.6, = 0.012 S/m for grounds.

The parameter values of building height distribution for typical cases are given in Table 18. Building sizes are 30 × 20 m2, 25 × 20 m2, and 20 × 20 m2 for high, middle and low rise. Building densities are 40%, 30%, and 20% for high, middle and low density.

TABLE 18

Parameters of building height distribution for statistical modelling

Path morphology Rayleighparameter

Range of building height distribution

(m)

Average building height

(m)

HRHD18

12.3~78.6 34.8HRMD 12.5~70.8 34.4HRLD 13.2~68.0 34.2MRHD

107.3~41.2 19.5

MRMD 7.2~39.0 19.6MRLD 7.4~40.4 19.4LRHD

62.1~23.1 9.1

LRMD 2.5~22.2 9.4LRLD 2.5~23.5 9.5

11.3 Path loss model

The path loss model in this recommendation is given by:

PL=PL0+10⋅n⋅log10( d )+S                 (dB) (68)

PL0=−27 . 5+20⋅log10( f )                 (dB) (69)

where n is the path loss exponent. S is a random variable representing the random scatter around the regression line with normal distribution, and the standard deviation of S is denoted as s. The units of f and d are MHz and metres, respectively.

The path loss parameters for typical cases of 9 path morphologies from statistical modelling at 3.705 GHz are summarized in Table 19. The values in the Table are fitted for all receivers at the height of 2 m located along the path at distances from 100 m to 800 m.

Rec. ITU-R P.1411-6 33

TABLE 19

Path loss parameters for 9 path morphologies at 3.705 GHz

Path morphologyTransmitting

antenna height(m)

Average building density

(%)n s

HRHD 50 40 3.3 9.3HRMD 50 30 2.9 6.3HRLD 50 20 2.5 3.6MRHD 30 40 2.8 4.7MRMD 30 30 2.6 4.9MRLD 30 20 2.3 2.7LRHD 20 40 2.4 1.3LRMD 20 30 2.3 1.8LRLD 20 20 2.2 1.8

11.4 Delay spread model

The r.m.s. delay spread can also be modelled as a function of distance. The r.m.s. delay spread along NLoS-dominant paths at distances from 100 m to 800 m can be modelled as a distance- dependent model given by:

DS= A⋅dB                 (nsec) (70)

The delay spread parameters for typical cases of 9 path morphologies from statistical modelling at 3.705 GHz are summarized in Table 20. The receiver heights are 2 m, and outliers are properly removed to obtain the fitted parameters.

TABLE 20

Delay spread parameters for 9 path morphologies at 3.705 GHz

Path morphologyTransmitting

antenna height(m)

Average building density

(%)

Delay spread(nsec)

A B

HRHD 50 40 237 0.072

HRMD 50 30 258 0.074

HRLD 50 20 256 0.11MRHD 30 40 224 0.095MRMD 30 30 196 0.12MRLD 30 20 172 0.19LRHD 20 40 163 0.18LRMD 20 30 116 0.23LRLD 20 20 90 0.29

34 Rec. ITU-R P.1411-6

11.5 Angular spread model

The angular spread of departure (ASD) and arrival (ASA) along the paths at distances from 100 m to 800 m can be modelled as a distance-dependent model given by:

ASD=α⋅d β                (degrees) (71)

ASA=γ⋅dδ                (degrees) (72)

The parameters of ASD and ASA for typical cases of 9 path morphologies from statistical modelling at 3.705 GHz are summarized in Table 21 and Table 22.

TABLE 21

ASD parameters for 9 path morphologies at 3.705 GHz

Path morphologyTransmitting

antenna height(m)

Average building density

(%)

HRHD 50 40 107 –0.13

HRMD 50 30 116 –0.18

HRLD 50 20 250 –0.31MRHD 30 40 115 –0.22MRMD 30 30 232 –0.33MRLD 30 20 264 –0.37LRHD 20 40 192 –0.33LRMD 20 30 141 –0.29LRLD 20 20 113 –0.24

TABLE 22

ASA parameters for 9 path morphologies at 3.705 GHz

Path morphologyTransmitting

antenna height(m)

Average building density

(%)

HRHD 50 40 214 –0.27

HRMD 50 30 147 –0.17

HRLD 50 20 140 –0.14MRHD 30 40 127 –0.15MRMD 30 30 143 –0.16MRLD 30 20 132 –0.13LRHD 20 40 109 –0.09LRMD 20 30 124 –0.11LRLD 20 20 94 –0.06

Rec. ITU-R P.1411-6 35